Extensive research effort is presently being expended to develop mass production capabilities for photovoltaic cells generating electrical energy from incident solar radiation. As used herein, a photovoltaic or solar panel refers to an array of photovoltaic cells which may comprise silicon materials or polycrystalline thin films in a common glass substrate and connected in series or parallel configurations. The resulting solar panels are fragile and should desirably be provided with a frame or other support in an overall power producing network.
While various concepts may be envisioned for mounting solar panels to a roof surface of a building, there are currently four basic generic mounting concepts: standoff, rack, direct and integral. The standoff and rack designs utilize frames typically constructed over the roofing shingles, the rack approach being used for flat or slightly sloping roofs while the standoff approach is spaced from the shingle surface at a parallel slope. In the direct mounting design the frame is secured directly to the roof sheathing and in the integral approach the frame is mounted on the roof rafters, forming a portion of the roof.
The most common mounting concept in current commercial use is the standoff design, in part, because it causes the least disruption to the roof and building occupants. The frames in such designs are typically of the picture-frame variety by which solar panels are engaged at the peripheral edges with a portion of the frame border usually extending disadvantageously onto and over an outer surface area of the solar panel. As, with current techniques, the power conversion efficiency of solar panels is relatively low, it is highly desirable to provide a high density array of solar panels and to make accessible to solar incident radiation as much surface area of the panels as possible. The picture-frame type panel mounting does not effectively provide such panel mounting, and, as these frames are commonly formed of metal, electrical grounding is usually required.
In addition, solar panel modules comprising solar panels and frames which are adapted for use in present standoff mounting designs are generally factory installed with electrical wiring hard-connected as by soldering or the like, such wiring being often disposed exteriorly of the module for interconnection to other modules. Not only does the externally exposed wiring present a safety and waterproofing problem, but the factory installed construction of the module does not lend itself for ready maintenance and repair.
Furthermore, the known commercial standoff designs utilize complex bracing and support structures for mounting to solar panel modules thereon. The spacing between the modules and the roof shingles is generally utilized to make electrical connections to the modules through junction boxes.
Accordingly, the solar panel mounting techniques of the known art are considered incapable of providing low cost installation in a high density panel array with ease of maintenance and repair. The present sophisticated packaging, in further consideration of moisture sealing and aesthetics, is not believed capable of meeting the desired needs of the solar energy industry.